Device for annealing metal rings



Aug. 11, 1931. F. LlNNHOFF 1,313,341

DEVICE FOR ANNEALING METAL RINGS Filed Nov. 18, 1929 4 -Fig.] 0J0 IfFig.2

lnvenfor:

Patented Aug. 11, 1931 UNITED 'STATES' PATENT OFFICE- IRANZ LINNHOFF, FEBEBSWALDE, GERMANY, ASSIGZNOR TO THE FIRM: HIRSCH, I 'KUPFER- ANDMESSINGWERKE AKT.-GES., OF EINOW/ MARK,

DEVICE FOR ANNEALING METAL KIN GS Application filed November 18, 1929,Serial No.

My invention relates to the annealing of metal rings, more particularlyto the annealin of metal rings of magnetizable material.

etal bands have been annealed up to today by winding them into rings andheating them 1n an annealing furnace by resistance or inductive heating.The resistance heating has the disadvantage the heat can hardlypenetrate through the outer layers of the rings to the inner layersbecause there are heat-insu lating air spaces between the metal layers.Therefore this annealing method requires comparatively much heatingenergy. Besides, owing to the slow annealing of the inner layers, themetal does not attain the desired uniform fine grained texture.

The inductive heating is more eflicient but the known inductive heatingdevices are also disfavourable in. some way because with the knowndevices the greatest part of the magnetic flux is flowing through air sothat a strong stray field arises which causes energy losses as well as abad power factor.

The object of my invention is to provide a device for annealing metalrings or rings of metal bands which makes it possible to anneal themetal very quickly without considerable energy losses and which workswith a good power factor. c

I have illustrated my invention in the accompanying drawings in whichFig. 1 is a cross-section Fig. 2 is a top plan view of an annealingdevice; and

Fig. 3 is a cross section of a furnace for bright-annealin metals.

Referring to igs. 1 and 2, the annealing material consisting of a ring 1of metal bands is introduced into the lower art 2" of a subdividedannular induction 0011. This part annular bar 5. The upper and lowerparts of the coil are connected by 'springy contacts which are provided'on the outer limbs of the 408,099, and in Germany November 24, 1928.

lower conductor 2. When the upper part 4 is applied to the lower part ofthe coil, the springy contacts clasp the outer ends of the radialconductors 4: and thus close the circuit. 1

.As the current supply is connected by the conductors 6 and 10 to theannular bars 3 and 5, the conductors form a continuous winding runninground the ring 1 which acts as the iron core of a Gramine ring armaturem and is heated by the hysteresis energy as v well as by the eddycurrents very quickly and uniformly. Smce with this arrangement thewhole magnetic flux is flowing in iron, the stray-losses are minimal. eIn Fig. 3, the'lower part of the coil is 10- cated within a 0t 7 ofrefractory material which after having brought in the annealing materialand having completed the'coil can be closed by the oil-sealed cover 8hermetically. The pot is provided'with tubes 9 and 109 for supplying aninert gas into it in order to prevent the oxidation of the annealingmaterial during the annealing process.

Having now particularly described and ascertained the nature of myinvention and in what manner the same is to be performed, what I claimis: 1. In a device for annealing metal rings an induction coil formingthe winding of a ring armature the core- .of which being formed by theannealing material. a 2.v In a device for-annealing rings of mag--netizable material, an induction coil forming the winding of a ringarmature the core 35 of which being formed by the annealing material. V3. In a device for annealing metal rings, an induction coil forming thewinding of a ring armature the core of which is formed by the annealingmaterial, the windingsof the coil being subdivided so as to be adaptedtoreceive the annealing material. 4. In a. device for annealing rings ofmagnetizable metal, a substantially annular in-. duction coil, each.winding of which consist ing of two parts and means for connecting saidtwo parts one to another.

5. In a device for annealing rings of magnetizable metal, asubstantially annular induction coil, each winding of which consistingof two parts, and means for connecting said two parts, the upper part ofthe windings being adapted to be removed.

5 6. In a device for annealing rings of magnetizable metal, asubstantially annular induction coil each winding of which consisting oftwo parts, the lower part comprising U-shapedi conductors the innerlimbs of which being connected by an annular conducting bar, and theupper part comprising radially extending conductors the inner ends ofwhich being connected to one another by an annular conducting bar andthe outer ends being adapted to be connected to the outer limbs of saidU-shaped conductors.

7. In a device for annealing rings of magnetizable metal, asubstantially annular induction coil each winding of which consisting oftwo parts, the lower part comprising U-shaped conductors the inner limbsof which being connected to one another by an annular conducting bar,and the upper part comprising radially extending conductors 5 the innerends of which being connected to one another by an annular conductingbar, the outer ends of said radially extending conductors and the upperends of the outer limbs of said U-shaped conductors forming;

the plug and receptacle of a plug connection;

8. In a device for bright-annealing rings of magnetizable metal, aninduction coil forming the winding of a ring armature the core of whichbeing formed by the annealing material and a pot adapted to be sealedhermetically, said coil being located within said pot, and means formaintaining an atmosphere of inert gases within said pot.

In testimony whereof I afiix my signature.

FRANZ LIN NHOFF.

